A Hobart and William Smith physics professor is celebrating another milestone for a scientific collaboration focused on detecting gravitational waves.

The LIGO Scientific Collaboration, of which Hobart and William Smith physics professor Steven Penn is a prize-winning scientist, and the Virgo collaboration have reported their first joint discovery of gravitational waves.

This is the fourth announced detection of a binary black hole system and the first significant gravitational-wave signal recorded by the Virgo detector. It highlights the scientific potential of a three-detector network of gravitational-wave detection, Penn said.

Researchers announced Sept. 27 that the three-detector observation was made Aug. 14. The two Laser Interferometer Gravitational-Wave Observatory detectors in Livingston, La., and Hanford, Wash., as well as the Virgo detector near Pisa, Italy, detected a transient gravitational-wave signal produced by the collision of two black holes 1.8 billion light years away.